1. Field of Invention
The present invention relates to a photographic device, and more particularly to a photographic flashlight which is capable of producing flashes which is suitably diffused and diffracted for achieving an optimal photographic performance.
2. Description of Related Arts
A conventional flashlight usually comprises a light source which is capable of producing high-intensity flashlight, and a flash housing for securely mounting the light source. The flash housing is then mounted onto a wide variety of devices, such as cameras, for providing flashes for particular purposes, such as providing adequate illumination when the camera is taking pictures.
As a matter of fact, there are several disadvantages in relation to conventional flashlights. For example, the flashes produced by conventional flashlights may be too short or too long in time so that the objects being shot are not properly illuminated. Similarly, the intensity of the flashes may be too low or too high such that the illumination produced by the flashlights is not suitable or optimal for the particular purposes for which the flashlights are utilized.
Because of these disadvantages, several improvements over conventional flashlights have been developed. First, U.S. Pat. No. 4,066,885 to Weinburg generally discloses a light extractor-diffuser for a camera flash unit. The device bounces the light off a central bilateral trapezoidal panel which is supported by two triangular shapes on its sides. The object of that invention is to provide an improved bounce flash adapter for photography, so as to achieve proper illumination without glare for a target object. The problem with this conventional device is that the light extractor-diffuser is inflexible in that the diffusion of light is largely due to the geometry of the diffuser, notable the several triangular panels, and the trapezoidal panel thereof. As a result, adjustment of the diffusion effect of that conventional diffuser requires adjustment of the angle of inclination between the triangular panels and the trapezoidal panel. The patent itself discloses a 45° degree angle of inclination and a 60° angle of inclination. What matters is that diffusers of different angles require different manufacturing equipments and this substantially increases the relevant manufacturing cost.
Second, U.S. patent application of 2006/0109640 to Fong generally discloses a photographic light diffuser comprising a semi-transparent cowl and a removable semi transparent cover detachably mounted on the cowl. The invention disclosed in that patent aims to solve the problem of immobility and inconvenient use of conventional light diffusers or flashlights in outdoor environment. It does not, however, address the problems for conventional flashlights as described above.
Third, U.S. patent application of 2006/0109641 to Fong discloses a photographic light diffusing device comprising a partially transparent cowl, wherein the cowl has a plurality of ribs for achieving studio-quality lighting performance. According to the published patent application, the ribs allow light to be more effectively diffused as it passes through the cowl and into the area in which a photograph is being taken. Now the problem with this invention is that while the diffuser may work fairly well for producing a studio-quality lighting performance, it is certainly not ideal for producing an adequately long-lasting flashing effect. For example, when a photographer wishes to expose the film for a relatively long period of time, such as when the photographer wishes to introduce a particular aesthetic effect for the resulting photographs, the photographer may require a more long-lasting flash instead of conventional flash produced by conventional flashlights. Obviously, one may alter the illumination time of the light source in order to produce flashes with prolonged period of time. While this is theoretically possible, it is not feasible or even desirable in practice. This is because when the illumination time of the light source is lengthened, the overall aesthetic effect of the photograph may be undesirably altered in addition to what is expected from prolonging the illumination time of the light source.
Finally, a general problem about conventional light diffusers: almost all conventional light diffusers fail to achieve a satisfactorily uniform lighting performance. This is partly due to the fact that the geometry of the cowl or the flash housing does not match with the physical nature of light propagation.